The electronic tester referred to above is used for testing electrical or electronic devices such as printed circuit boards, integrated circuits or the like for accuracy and correct performance. Known resilient contact pins (see for example, Kruger, "Prufmittel zur elektrischen Prufung von Leiterplatten fur Uhren", Jahrbuch der Deutschen Gesellschaft fur Chronometrie, Band 30, 1979, pp. 269-276; German Open Patent Application No. 35 07 464) has a cylinder in which the round cross section massive plunger head of the plunger member is supported so as to be axially slidable.
This plunger head is spring loaded by a compressed coil spring against whose force it is pushed during testing of the electronic device by the tester.
The spring must exert a comparatively large contact force, primarily about 50-300 cN, inspite of the comparatively small size of such a resilient contact pin.
The electric contact resistance between the parts of this resilient contact pin increases the electrical current flow resistance and it increase as usual with the number of load cycles.
The plunger member and the cylinder of the known resilient contact pin are made by machining, e.g. on a lathe and the spring is made on an automatic spring winder. According to the special application involved the parts are galvanically coated and assembled in manually operated or automatic devices. Even when the individual manufacturing steps occur in an automatic machine, the cost for manufacture of such high quality resilient contact pins is comparatively high.